Method of and apparatus for compression forging of components

ABSTRACT

A method of, and apparatus for, compression forging of components in which a bar section is pre-shaped by upsetting in a direction along its axis. The pre-shaped bar section is then supported by its ends between a pair of die faces and is deformed to a shape close to its final shape by transverse flow pressing. The shaped bar section is then ejected from the dies and is transferred to means for removing burrs from the bar section. Preferably at least one of the die faces is sprayed with a cooling fluid after the shaped bar section is ejected.

. 3 7} m H] l 3% States Patent 91 [1 3,733,73 Ballmer May 22, 1973 54 METHOD OF AND APPARATUS FOR 3,399,560 9/1968 Connolly ..72 377 COMPRESSION FORGING OF 3,195,769 7/1965 Miller ..72/360 3,124,876 3/1964 Putetti ..72/334 [75] Inventor: Ernst Ballmer, Basel, Switzerland primary Ri h d J H b [73] Assignee: F.B. Hatebur AG, Basel, Switzer Assistant Examiner-Robert Rogers [and Attorney-Kurt Kelman [2]] Appl 149743 A method of, and apparatus for, compression forging of components in which a bar section is pre-shaped by [30] Foreign Application Priority Data upsetting in a direction along its axis. The pre-shaped bar section is then supported by its ends between a .I 1

une 971 Germany P 20 27 692 0 pair of die faces and 1s deformed to a shape close to lts 52 us. Cl. 372/332 72/342 72/377 final shape by transverse Pressing The Shaped 29/33 bar section is then ejected from the dies and is trans- 51 Int. Cl ..B2ld 28/00, B2ld 37/16 ferred means for ramming burrs fmm the bar [58] Field of Search ..72/338, 334, 360, tion- Preferably at least one of the die faces is p y 72/377, 342, 332; 29/33 A with a cooling fluid after the shaped bar section is ejected. 56 1 References cued 11 Claims, 28 Drawing Figures UNITED STATES PATENTS 3,503,123 3/1970 Law ..72/377 PATENIEU 1111' 2 21975 SHEET 01 1 16 INVEN ERNST BAL LM PATENTEL HLYZZ I975 SHEET [13 [1F 16 Ir l l g- Mb FIG.3

INVENTOR. ERNST BAL LMER PAIENTE MAY 2 21973 SHEET UH 0F 16 v p A m VENTOR. ERNST BALLMER P/TIENTED SHEET 5 16 INVENT ERNST BALLM PATENTEL 22 5 SHEET us OF 1 FIG.6

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INVENTOR. ERNST BALLMER fl] FIG. 23

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ERNST BALLMER METHOD OF AND APPARATUS FOR COMPRESSION FORGING OF COMPONENTS The present invention relates to a process of, and apparatus for, the compression forging of a blank in the form of a bar section.

A particular, but not exclusive application of the invention is in the production of components which have delimiting faces variously spaced from the press axis, in particular forgings for articulated cross-pieces, tripods, T-irons, and the threaded pipe elbows.

The rational manufacture of such elements had hitherto still invovled considerable disadvantages. In one known process for the manufacture of the articulation crosspieces required for universal joints (knuckle joints), work commences from a rectangular bar out of which a predetermined number of articulation crosspieces (preferably four) are first of all pre-pressed, in a row disposed side-by-side, the crosspieces then being punched out. With this method, there is produced a relatively large amount of material waste, since of the original rectangular bar only the portions punched-out in the shape of cruciform elements can be used. Furthermore for the simultaneous punching-out of the four crosspieces (cruciform elements) four different dies have to be used, so that the articulation crosspieces exhibit dimensional deviations which, although small, are nevertheless noticeable and which are a source of difficulty during the subsequent machining and also during operation of the universal joint. Furthermore, the articulation crosspieces thus manufactured have a burr (or flash) following the entire peripheral line and located in particular at the end faces of the cross arms, which makes subsequent machining difficult and costly. To this must be added the fact that, with the conventional manufacturing process, the grain of the material extends parallel in all sections of the articulation crosspiece, so that the finished shaped component exhibits a diminished degree of toughness or reduced stresswithstanding properties in predetermined directions of an applied force.

According to one aspect of the present invention there is provided a process for the compression forging of components from blanks in the form of bar sections, which process includes pre-shaping a bar section by upsetting the bar section in a direction along its longitudinal axis, and supporting the upset bar section axially between co-operating dies and deforming the upset bar section to form a shaped component, whose shape is close to its final shape by transverse flow pressing of the upset bar section between the co-operating dies.

In one form of the process in accordance with the present invention a blank is, after being severed from the bar, retained held against an upsetting means in a first deformation station between a holding means which is displaceable coaxially with respect to the press ram and is under resilient pressure, and is then, by axial upsetting with the aid of the press ram, preshaped to a pressing. The pressing is then introduced, in a second deformation station, between two die halves which are disposed opposite each other and is, by a relative movement of the die halves and by means of transverse flow pressing deformed to a forged component similar to the final shape.

Thus, this process permits rational manufacture of the shaped components concerned, by automatic methods at a higher production rate, in a plurality of deformation stages following one after the other, this being something which hitherto had not been possible. In fact, it was considered that the problems connected therewith, such as the dimensional accuracy of the shaped components, the controlled discharge of the numerous sheared-off small burrs, the limitations of die wear, and the cooling of the matrix-side die halves, could not, in view of the enormous material stressing and the high production rate required, be solved together. The process in accordance with the present invention affords this solution and in this way permits a considerable increase in production since, now, on an apparatus operating in accordance with the invention approximately pieces per minute can be produced as compared with the hitherto obtaining production of at maximum approximately 20 pieces per minute. Since all the shaped components travel through the same dies, they are absolutely identical and can be further machined without difficulty. Furthermore, however, also the grain configuration of the material resulting from deformation may be considered to be ideal in the case of the present invention. According to the abovementioned known process, the grain configuration is, for example in the manufacture of universal joints, practically parallel to the common axis of two articulation cross arms disposed opposite each other. Whereas in the process according to the present invention, the grain run in the blank is, before deformation, parallel to the press axis and, during the upsetting step, the fibers are bulged out (see FIGS. 2 and 5 of the accompanying drawings) thus imparting an extraordinary degree of toughness to the material.

The intentional burr (or flash) produced during deformation may be considered to constitute a material buffer for compensating the volume differences in the bar section resulting from tolerance variations in the raw material. In the case of articulation crosspieces formed with an axial bore (FIGS. 17 and 18 of the accompanying drawings) the burr formation can be avoided because the excess material may be taken up in a portion to be punched out to form an aperture. It is also possible to restrict the aforementioned volume variations to a minimum from the outset, by rough turning or drawing the rolled bar stock. However, the formation of a burr will in many cases be unavoidable for reasons connected with costs and manufacturing techniques. In these cases, the process according to the invention may be supplemented by the arrangement whereby the two die halves are, at the points corresponding to the recesses in the shaped component (in view of the burr formation) approached to each other only up to a predetermined spaced relationship, the shaped component being ejected out of the die by at least one ejector and displaced by means of a transverse conveying device into a holding-on position before a burr removing station, whereupon the burr is sheared off in the burr-removal station between a female punching die and a male punching die, both the shaped component and also the sheared-off burr being retained until they are able, after the return travel of the male punch die to drop down unhindered.

According to a second aspect of the present invention there is provided apparatus for the compression forging of components from blanks in the form of bar sections, comprising means for pre-shaping a bar section by upsetting it in a direction along its longitudinal axis, and means for supporting the upset bar section axially between co-operating dies having a shape close to the final shape of the component and for applying a pressure to the dies to deform the upset bar section into the dies by transverse flow pressing.

In one embodiment of the apparatus made in accordance with the present invention a blank severed from a bar is fed, in chronological sequence by a transverse conveying means, to an upsetting station and from the latter to a deformation station having a die. The upsetting station has a ram mounted for sliding in the pressing direction, and coaxial thereto, a fixed counterholding means arranged opposite in spaced relationship, a holding pin resiliently pressed in the direction of the counter-holding means being mounted coaxially and for displacement in the ram. A female die of the deformation station has a central ejector mounted for coaxial sliding therein, and the coaxially oppositely arranged ram or male die has a holding pin mounted for coaxial sliding movement therein and is resiliently urged in the direction of the female die. The axial movement of the ejector relative to the ram or male die movement is so synchronized that the pressing first of all adopts a holding-on position between the holding pin and the ejector and, subsequently, due to axial advance of the male die and corresponding withdrawal of the ejector, is adapted to be pushed into the die mound and deformed. In the female die body there is arranged, for each of the shaped component sections projecting laterally outwardly, a controlled ejector pin mounted for sliding parallel to the central ejector. Furthermore the two die halves disposed opposite each other are embraced by an annular matrix sealing the said halves off radially.

Preferably a burr-removing station is provided at which there are arranged tool elements provided with burr-removal edges, the female die being provided with a holding pin for retaining the shaped component in a holding-on position, there being furthermore provided in the ram body of the burr-removal station, for each burr on the shaped component to be punched off, a holding pin mounted for axial sliding movement and subjected to the influence of a resilient means which presses the holding pin during and after the burrremoval step against the associated burr and presses the latter against a front face, facing it, of the female die.

The ejector which is mounted in the deformation station and has the shape of an ejector pin may have a blind aperture bore connected to a source of coolant, there being formed in the walls of the ejector pin at least one passage bore extending practically transversely of the blind aperture bore and debouching into the same, to serve for the outflow of coolant on to the female-die-side die faces.

With this arrangement, there is advantageously arranged within the zone of movement of the female-dieside ejector pin a resilient means pressing the ejector pin back to the forward edge of the female die after reaching the front dead center. The resilient means may for example be a cup spring assembly, the ejector pin having a collar rigidly connected therewith and which, towards the end of the ejection movement, impinges on the cup spring assembly and biases the latter.

In a further embodiment, the ejector has a cylindrical section formed with a cooling bore and a sleeve mounted for sliding on the periphery of the said section, the sleeve being connected via two ejector pins of varying diameter arranged in a stepped bore with an actuating rod, and the female-die-side pin projecting, before commencement of the ejection step, to a predetermined extent into the bore of the thicker pin so that, due to the movement of the actuating rod first of all only the sleeve is advanced by the aforesaid amount and then the sleeve with the ejector section is advanced to a further extent.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows, as a simplified sectional view, an upsetting station into which a rod section to be deformed has just been introduced,

FIG. 2 shows the upsetting station according to FIG. 1 shortly after completion of the upsetting step,

FIG. 3 is a diagrammatic sectional view of a deformation station, showing the pre-upset pressing shortly after withdrawal of conveying tongs or grippers,

FIGS. 4 to 8 show the individual processing phases through which the pressing passes in the deformation station according to FIG. 3,

FIG. 9 is a simplified sectional view of a burr-removal station, showing the blank shortly before initiation of the punching step,

FIGS. 10 to 12 show individual phases through which the blank passes in the de-burring station, in chronological sequence,

FIGS. 13 and 14a to 14c each show a variant of the deformation station shown in FIG. 3, and

FIGS. 15 to 26 show examples of shaped components which may be produced on the device illustrated.

In the drawings, which as an example of an embodiment show the manufacture of an articulation crosspiece according to FIGS. 15 and 16 on an automatic transverse conveying press, the rod section sheared off from round stock has been designated 1. In the case of the transverse conveying press illustrated, the round bars which have a length of 4 to 6 rn. are first of all pushed on rollers through a heating means, heated to forging temperature and fed to the subsequent shearing or severing operation. There, sections of predetermined length, corresponding to the required blank weight, are severed transversely of the machine axis. A shear blade 2 and a special holding finger 3 convey the rod section in the direction of the arrow 4 into position before the upsetting station shown in FIG. 1. The upsetting station has a ram or male die 6 mounted for sliding movement in the pressing direction, i.e. in the direction of the arrow 5, and also disposed coaxially opposite the ram a stationary upsetting plate 7. The ram 6 installed in a ram holder 8, with interpositioning of a sleeve or bush 9, may be driven for example by means of a cam disc or a crank mechanism; this drive is immaterial in the present connection and has therefore not been shown.

A retaining or holding pin 10 is mounted for coaxial sliding movement within a stepped bore in the ram 6. The holding pin 10 is subjected to the influence of a spring 11 tending continuously to press it into the position shown in FIG. 1. In this position, the shear blade 2 which is shown in broken lines has, together with the holding finger 3 after release of the bar section 1, been withdrawn from the latter and the bar section is then retained by spring pressure between the holding pin It) and the front face of the upsetting pin '7. This intermediate position is necessary in order to ensure entirely satisfactory withdrawal of the shear blade 2 and the holding finger 3 before initiation of the upsetting step.

The fixed upsetting plate 7, mounted on an anvil 12 is retained in a mounting sleeve 13. The upsetting plate may be supplied with coolant via a central bore 14.

Whilst the shear blade 2 has, together with the holding finger 3, been released from the section 1 and has travelled back into its starting position for shearing-off and engaging the next bar section, the ram 6 is advanced in the direction of arrow 5. As this takes place, the holding finger 10 is pushed, accompanied by compression of the spring 11, further into the ram 6. As soon as the front face 6a of the ram is flush with that of the holding finger 10, i.e. on impingement thereof on the section 1, also the holding finger 10 impinges on a stop and the bar section 1 is then pressed by the ram 6 and the holding finger 10, jointly, against the upsetting plate 7. During this procedure, the end phase of which is shown in FIG. 2, the bar section is deformed to afford a barrel-shaped pressing having precisely predetermined dimensions. After completion of this upsetting step, the ram holder 8, with the ram 6, is withdrawn in the direction of arrow 16, whereas the holding finger 10 still retains its position shown in FIG. 2 and holds the pressing 15 fast, until the latter is, for the purpose of further transport to the deformation station, engaged by a pair of grippers (not shown).

FIG. 3 shows the deformation station in which the pre-upset pressing 15 is put into the desired shape by means of a transverse flow pressing step. The deformation station has a ram 17 into the front face of which a die half 180 has been machined. A spring-biassed holding pin 19 is mounted for sliding movement within the ram 17, coaxial thereto. A stationary female die 20 is disposed opposite the ram or male die 17. A die half 1817 is provided in the front face of the female die 20 which faces the ram or male die 17. The die 20 is retained in a female die holder 22 by an annular matrix 21 interposed therebetween. The die 20 is formed with a central bore within which an ejector pin 23, coaxial with the ram 17 is slidable. Furthermore, there is mounted in the female die 20 a plurality of ejector pins 24 the function of which will be described later. All the ejector pins 23 and 24 are connected with a sliding piston or plunger 25 controlled by a cam disc. The latter is unimportant for an understanding of the idea of the invention it has therefore not been shown.

The central ejector pin 23 is formed with a blind aperture bore 23a connected to which are transversely extending outflow ducts 25, 26, 27, 28 and so on. The central bore 23a is connected to a source of coolant.

In the position shown in FIG. 3, the pressing 15 has, after being introduced by the transverse conveying grippers (not shown) in the direction of arrow 29, been received by the facing end faces of the ejector pin 23 and of the holding pin 19. The pressing 15 is thus retained in its position according to FIG. 3, so that the grippers have been able to open and return to the upsetting station. Then, the deformation step proper is initiated, the ram or male die 17 being first of all displaced in the direction of arrow 30 (FIG. 4) towards the female die. As soon as the die half 18a impinges on the facing end face of the pressing 15, also the holding pin 19 reaches a position wherein its end face 19a is flush with the face of the die half 18a. On further advance of the ram 17 in the direction of the arrow 30, first of all the central ejector pin 23, and therewith via the slide piston 25 also the ejector pins 24, are pushed back into the position shown in FIG. 4. At this instant, i.e. on impingement of the barrel-shaped pressing 15 on the female-die-side (or matrix side) die half 18b, the flow pressing step commences.

As FIGS. 5 and 6 show, the pressing 15 is so pressedin between the ram 17 and the female die 20 that it completely fills the two die halves 18a and 1812. In this connection, special attention should be given to the grain run of the pressing material indicated in FIG. 5, which, in contradistinction to what obtains with hitherto known manufacturing methods, guarantees an especially high degree of resistance to stressing and in particular toughness of the final product.

As soon as the ram 17 has reached its front dead cen ter according to FIG. 6, the pressing is completely shaped to afford an articulation crosspiece blank 31. In this connection, it should be observed that the ram 17 has been able to approach the female die 20 only up to a position having reciprocal spacing a. For an understanding of this step, which is provided in view of burr formation, reference will first of all be made to the embodiment shown in FIGS. 15 and 16 of the articulation crosspiece to be manufactured.

The crosspiece (or cruciform member) designated 31 as a whole and whereof FIG. 16 shows a plan view and FIG. 15 a section taken along the line XV-XV of FIG. 16, is a shaped component the individual section of which exhibit varying radial spacings relative to the axis M. One of the spacings has been designated r by way of example in FIG. 16, whereas the other has been designated R. This varying radial dimensioning of the various shaped component sections has, in the case of cross flow" pressing on automatic transverse convey.- ing presses hitherto been considered to represent a very considerable obstacle which could not be overcome using conventional means. In the case of the abovedescribed process, there is left at the interspaces between the shaped component sections of greater radial extent (R), in the deformation phase, a burr 32 which is sheared-off in a subsequent de-burring operation.

After deformation has been effected, the ram 17 is lifted off from the female die 20 in the direction of arrow 33. Meanwhile, the holding pin 19 retains its position, under the influence of the spring acting on it and ejects the crosspiece blank 31 out of the die half 18a of the ram 17. The blank 31 is thus retained by the holding pin 19 in the female-die-side die half 18b.

On further travel-back of the ram 17 in the direction of the arrow 33 (FIG. 7) however, the holding pin 19 impinges through the agency of its oblique shoulder 19:: on a corresponding shoulder in the central bore of the ram 17 and, from this instant on, is entrained by the ram 17. Then, the female-die-side ejectors 23 and 24 are able to eject the crosspiece blank 31 out of the female die-side die half 18b and to surrender it to the transport grippers (not shown) which are in the readiness position. In this position, which is shown in FIG. 8, the mouths of the transversely extending outflow ducts 25, 26 and 27 of the central ejector pin 23 are freed and the cooling water entering through the central bore 230 is able to flow out in controlled manner onto the female-die-side die half 18b. It should be observed that the position and angle of inclination of each duct is so selected that the emerging coolant jets impinges precisely on those parts of the female die which are most stressed and therefore also hottest. In this 

1. Process for the compression forging of components from blanks in the form of bar sections, comprising the steps of:
 2. pre-shaping a bar section by upsetting said bar section in a direction along its longitudinal axis; b. supporting the upset bar section axially between co-operating dies and deforming the upset bar section to form a shaped component whose shape is close to its final shape by transverse flow pressing of said upset bar section between said cooperating dies; c. transferring said shaped component to a third station whereat burrs are removed from said shaped component by holding said shaped component in shaped members and shearing the burrs from said component using co-operating male and female punching dies; and d. retaining said shaped component and the sheared-off burrs in position until each male punching die has returned to its starting position, whereafter said shaped component and said sheared-off burrs are released.
 2. Apparatus for the compression forging of components from blanks in the form of bar sections, said apparatus comprising, in combination: a. means at one station for pre-shaping a bar section by upsetting it in a direction along its longitudinal axis; b. a set of co-operating male and female die halves each having a shaped end having a shape close to the final shape of the component to be forged at another station; c. means for supporting the upset bar section axially between said set of dies; d. a resiliently mounted retaining means mounted coaxially in the male die half so as to be relatively moveable thereto; e. an ejector slidably mounted coaxially in the female die half; f. a controlled ejector pin movable parallel to said ejector; g. pressure applying means for applying a pressure to at least one die half of said co-operating die halves so that said upset bar section is deformed by transverse flow pressing into a shaped component; and h. an annular matrix positioned to enclose the die halves when closed by said pressure applying means.
 2. pre-shaping a bar section by upsetting said bar section in a direction along its longitudinal axis; b. supporting the upset bar section axially between co-operating dies and deforming the upset bar section to form a shaped component whose shape is close to its final shape by transverse flow pressing of said upset bar section between said cooperating dies; c. transferring said shaped component to a third station whereat burrs are removed from said shaped component by holding said shaped component in shaped members and shearing the burrs from said component using co-operating male and female punching dies; and d. retaining said shaped component and the sheared-off burrs in position until each male punching die has returned to its starting position, whereafter said shaped component and said sheared-off burrs are released.
 3. Process as defined in claim 1, further comprising the step of (e) spraying at least one of said co-operating dies with a coolant.
 4. Process as defined in claim 1, in which said preshaping step takes place at a first deforming station at which said bar section is resiliently retained against an upsetting means and is upset by a ram pressing said bar section against the upsetting means, and in which the deforming step takes place at a second station at which said upset bar section is introduced axially between co-operating male and female die halves.
 5. Process as defined in claim 1, in which at least said female die half is sprayed with a coolant immediately after said shaped component has been ejected from said female die half, and in which said coolant is sprayed from at least one bore provided in an ejector pin associated with said female die half.
 6. ApparatUs as defined in claim 2, further comprising (i) spraying means for spraying at least one die of said co-operating dies with a coolant.
 7. Apparatus as defined in claim 2, further comprising a burr removal station having male and female punching dies, an ejector mounted in the female punching die, a retaining pin for retaining the shaped component against said female punching die after said male punching die has sheared-off each burr, and a second retaining pin for each burr to be punched off mounted for movement parallel to said male punching die, each second retaining pin adapted to hold its associated burr against said female punching die during and after the shearing operation.
 8. Apparatus as defined in claim 2, in which the ejector in said female die half has a blind aperture bore therein connected to a coolant source, at least one passage bore in the wall of the ejector pin extending practically transversely of said blind aperture bore and debouching into the same, to serve for outflow of the coolant on to said shaped end of the female die half.
 9. Apparatus as defined in claim 8, further comprising a resilient means which is adapted to retract said ejector after it has reached the forward dead-center position on the front edge of said shaped end of said female die half.
 10. Apparatus as defined in claim 9, in which said resilient means is a cup spring assembly and in which said ejector has a collar which is rigidly connected therewith and which is adapted, towards the end of the ejection movement to impinge on the cup spring assembly and biases the latter.
 11. Apparatus as defined in claim 2, in which said ejector has a cylindrical section formed with a cooling bore and a sleeve mounted for sliding at the periphery of the said section; and in which the sleeve is connected, via two ejector pins of different diameters, and arranged one behind the other in a stepped bore, with an actuating rod, said smaller diameter pin projecting, before the commencement of the ejection step, by a predetermined amount into a bore of said thicker ejector pin, whereby due to the movement of said actuating rod, first of all only said sleeve is advanced by said predetermined amount and then said sleeve and said cylindrical section are advanced by a further amount. 